In coding theory, an erasure is a potential error with a known location. When receiving a codeword transmitted over a noisy channel, or reading a codeword from a memory device, unreliable bits in the codeword may be flagged as erasures. Flagging a symbol as an erasure typically uses the correction strength of only half of a symbol.
Reed-Solomon (RS) codes are non-binary cyclic error-correcting codes invented by Irving S. Reed and Gustave Solomon. RS codes may detect and correct multiple random errors. Moreover, RS codes may detect and correct combinations of errors and erasures as an erasure code. Furthermore, RS codes may also detect and correct multiple-burst bit-errors.
The Berlekamp-Massey algorithm (BMA) may be used in RS codes to find the error locator polynomial, for calculating error values for error decoding. However, BMA may not work correctly if the number of erasures is greater than the nominal error correction strength of the code.